Mechanical stoker



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P. ROHAN. MECHANICAL STOKER. No. 451,622. Patented May 5, 1891.

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6 Sheets-Sheet 4. P. ROHAN.

MECHANICAL STOKER.

No. 451,622. Patented May5, 1891.

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MECHANICAL STOKER.

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(No Model.) 6 Sheets-Sheet 6. P. ROHAN.

MECHANICAL STOKER. v No. 451,622. Patented May 5,1891.

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UNITED STATES PATENT OFFICE.

PHILIP ROI'IAN, OF ST. LOUIS, MISSOURI.

MECHANICAL STOKER.

SPECIFICATION forming part of Letters Patent No. 451,622, dated May 5, 1891.

Application filed May 17, 1890. Serial No. 352,171. (No model.)

thefollowing is such a full, clear, and exact.

description as will enable any one skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, forming part of this specification.

The object of the invention is to mechanically feed fuel to the fire-grate of a furnace and mechanically stoke such fuel. This is done in my invention by a revolving firegrate made in sections and suitably rotated by mechanism driven, preferably, by the prime motor, for which force is generated by the consumption of fuel in the furnace. The said sections of the fire-grate as they rotate are automatically raised and lowered to stoke the fire. Mechanism is also provided and preferably driven by the prime motor, whereby a regular supply of coal is automatically dealt out to the fire. Said mechanism insures more thorough combustion of fuel, and thereby effects economy and prevents smoke to a great extent. Mechanical stokers not only accomplish the foregoing purposes, but do away with manual labor, and thereby also effect economy. Furnaces and boilers provided with mechanical stokers are also less liable to sudden expansions and contractions due to the variation of heat in the ordi nary furnace. Boilers and furnaces provided with mechanical stokers are therefore subjected to less wear and tear and require less repairs than boilers and furnaces without mechanical stokers.

' The invention will be best understood by referring to the accompanying drawings, in which- Figure 1 is front elevation of a revolving fire-grate mechanical stoker made in accordance with my invention. Fig. 2 is a vertical section thereof on the line 2 2 of Fig. 1, looking in the direction of the arrows to said line, and showing a portion of the boiler. Fig. 3 is a plan of the same with the super-incum- 50 bent boiler removed and part of the fire-grate broken away to better illustrate the construction. Fig. 4 is a vertical sectional view on the line 4 4 of Fig. Fig. 5 is a vertical section on the line 5 5 of Fig. 3. Figs. 6 to 23, inclusive, are views of details, Figs. 8, 9, and being sectional views on the lines 8 8, 9 9, and 10 10, respectively, of Figs. 9, S, and 11, and Figs. 19 and 20 sectional views on the lines 19 19. and 20 20 of Figs. 20 and 19, respectively. The same figures of reference indicate the same parts throughout the several views.

The fire-grate is made up of sectors 30, the outer ends of which are carried by a circular bar 31, secured .to brackets 32 by bolts 33. These brackets extend from a worm-wheel 34, from which project lugs 35, over which the lower ends of the brackets 32 take, and to which said brackets are secured by keys 36. The worm-wheel 34 is braced to lugs 37, extending from an open circular piece or ring 38 at the center of the fire-grate by tie-rods 39. The said circular piece 38 has a central lug 40, extending therefrom. This lug 40 embraces and holds together a short post 41, made in two parts, and is firmly held to the head thereof. The post 41 has a hemispherical depression 42 therein at its lower end, which depression engages with a corresponding hemispherical part 43 upon the top of an adjustable screw-post 44, carried by a flanged pedestal 45, supported from the foundation of the apparatus. The post 41 revolves with the ring 38 and the fire-grate, and has a bearing on the top of the adjustable screw-post 44. Surrounding said post and the upper part of the adjustable screw-post 44 is a flanged housing 46, made in two parts bolted together with the flange thereof bolted to the upper plate of the flanged pedestal 45. The rods 39 take over h0oks47, carriedby lugs43, at intervals around the interior of the worm-wheel 34, and which may be cast integral therewith. hooksmay be carried by a plate 49, which slides in ways in said lugs, so that said hooks may be detached from the lugs when The said I necessary. Pins may be employed to hold the allow the outer ends of the grate-sectors to rise and fall and have suflicient play for the purpose of stoking the fire.

The circular bar 31 by means of housings 51, extending therefrom at various intervals around the same, forms bearings for antifriction wheels 52, which travel upon a stationary circular track 53. The circular track 53 is supported at intervals by brackets 54, which are bolted to a flanged rim 55, extending from the foundation of the furnace. These brackets are provided with a slot 56, by which they may be adjusted to fit the flange of the rail of the circular track. The rail is held to the brackets by means of a turned-over flange 57, that extends from said brackets, and a small flanged plate 58, which is placed between the rail andthe rim 55, and is bolted to the brackets, as clearly shown in Fig. 7. The flanged rim 55, which supports the rail is suitably stiffened at intervals by ribs 59. The circular bar31, which supports the outer ends of the grate-sectors, the wormwheel 31, and the brackets 82, which tie the circular bar 31 to the worm-wheel 34, revolve together and travel by means of the anti-friction rollers 52 over the track 53. The ribbed flanged rim 55, sustained by thefoundation of the furnace, also supports brackets at intervals around the same, which brackets are provided at their upper ends with antifriction rollers 61, and are suitably bolted to the flanged rim 55. The anti-friction rollers 61 are so arranged that their upper edges are above the normal level of the grate-sectors Sid-that is to say, are above the level of the circular bar 31, which supports the outer ends of the grate-sectors. Normally the sectors of the grate rest upon the circular bar 31; but as said sectors revolve they are raised by the anti-friction rollers 61 as they encounter them, and after passing the same drop upon the circular bar 31, and in their rise and fall stoke the fire. I

It is necessary and advisable that some means be employed whereby clinkers and the coal may be discharged from the fire-grate when necessary, and for this purpose I provide two series of curved fingers 62 and 623, which form a two-part hemispherical grate at the center of the grate-bar above the level of the same. These curved fingers are carried by semicircular pieces 64 and 65, each having aperforated lug G6 at one end and a spindle G7 at the other end, the arrangement being such that the spindle 67, carried by one set of fingers, engages the perforated lug 60, carried by the other set of fingers. The construction is such that either set of fingers may revolve upon the other, and for this purpose the lingers do not lie in the same plane, but break joint with each other. This hemispherical i'ire-grate is carried by a circular casting (58, which is in turn carried by the circular ring 38, before referred to. From the ring (58 extend upwardly slotted lugs (it), which receive spindles 67 of the two sets of curved fingers.

T0 is a small plug which closes the upper part of the slot in lugs 69 when the spindles G7 are placed in the same, and thus prevents the spindles and the curved fingers from being disengaged therefrom. It will be seen from this that either set of curved fingers may be thrown over upon the other, as shown in Fig. 21, so as to allow the contents of the grate to be discharged through the opening caused thereby or clinkers to be removed therefrom. If the curved fingers be put in the posit-ion shown in Fig. 21 and the grate revolved long enough, it will in the course of time remove most of the clinkers and discharge almost all the fuel from the fire-grate. My stoker is therefore not only self-feeding, but is also self-cleansing and self-discharging to a great extent.

The pivotal support at the center of the fire-grate and curved fingers may be raised and lowered by properly adjusting the screwpost it so as to make the inclination of the sectors of the fire-grate as great or as small as desired. In practice it will be found advantageous to have the crown or top of the curved fingers 62 and 63 above the level of the fuel upon the fire-grate for two reasons: first, that when so arranged air will pass through the curved fingers at the top, and will thus make more complete the combustion, and, second, the air so passing through the fingers keeps them comparatively cool and prevents them from burning out, which would happen were they entirely below the live coals upon the fire-grate. I will also mention here that I allow the sectors 30 of the fire-grate to stop short of the circular interior of the furnace, in order that air may also pass up around the circumference of thefire-gratc and make the combustion still more complete.

71 is a shaft, which is driven in any suitable way by any prime motor, but by preference will be driven by the motor for which steam is generated by the furnace herein shown. This shaft 71 carries a sprocket-wheel 72, by which motion maybe transmitted to it by said prime motor. It is suitably supported in bearings 73 and 71- from the base of the furnace, and has midway of it a worm 75, which meshes with the worm-wheel hereto referred to. \Vhen motion is transmitted to the shaft 71, it revolves the worm-wheel and fire-grate, and thereby stokes the fire. The speed of the shaft 71, which revolves the firegrate, may be increased or slowed down by suitable mechanism interposed between the prime motor and said shaft.

The supply of coal to the fire-grate I make automatic and control its introduction to the fire by mechanism preferably connected with the shaft 71, that revolves the fire-grate.

76 is a track suitably supported above the level of the furnace near the boiler, by which coal may be conveyed to and dumped upon a platform 77, which opens into a hopper 78, that delivers the coal to an inclosure 79, in which is placed a rotary feeder 80. This rolIO tary feeder is made up of disks and divided into quadrants by axial plates extending from the shaft or center of said feeder. The said feeder revolves in the direction of the arrow having no tail. (Shown in Fig. 2.)

Above the rotary feeder I place a series of cutting-plates 81, secured to an angle-bar 82, which is fastened to the side of the recepta- 01c 79. The purpose of these plates is to crush any large pieces of coal that may get into the feeder and clog the apparatus. The feeder 80 may be rotated at any required speed, depending on how much coal is to be delivered to the fire-grate. It is rigidly fastened to a shaft 83, which revolves in bearings Sat, carried by brackets 85, that are supported in turn from the base of the apparatus by brackets 86.

The receptacle '7 9 is provided with ahinge door 87, which is normally held locked by pivoted catches 88, whereby should the revolving feeder become clogged or get out of order it may be inspected and the trouble remedied.

The shaft 83 carries a series, preferably, of sprocket-wheels S9 of varying diameters,

- which are secured together and are fast upon a loosely-mounted sleeve 90, that has its bearing upon the remote end of the shaft 83. This sleeve 90 and the series of sprocket-wheels are rigidly fastened to a hollow wheel 91, which has journaled toit a small planet-Wheel 92,that meshes into a sun-wheel93, fast upon the shaft 83, and also engages with a circular gear 94, fast to the bearing 8+1, which supports the outer end of the shaft 83. The hollow wheel 91 is provided with a plate 95, which is secured to it and covers up the sun and planet wheels and prevents dust and dirt from getting into the gears. As the sprocketwheels revolve they carry around with them the sleeve 90, the wheel 91, and the planetwheel 92, which, as before described, is rotatably fastened to the hollow wheel 91. The circular translatory motion imparted to the rotary planet-wheel 92 causes it to travel around in the teeth of the fast circular gear 94: and also in the teeth of the sun-wheel 93, thereby driving said sun-wheel in an opposite direction to the rotationimparted to the Wheel 91 and slowing down the rate or rotation of the shaft 83. The sprocket-wheels 89 are revolved by a sprocket-chain 96, which engages with inverselyproportional corresponding sprocket-wheels 97 of varying diameters, arranged upon the shaft 71. By changing the sprocket-chain from one set of sprocket-wheels to another the shaft 83 and the revolving feeder 80 may be made to rotate at any speed desired, which in'practice is of course at a much slower rate of rotation than that of the shaft 71. The speed imparted to the shaft 83 depends upon the amount of coal that is required to be delivered to the .fire-grate and of course upon the amount of steam-pressure that is required and the quantity of steam to be used. The advantage of this construction is that the revolving feeder can be rotated through theinstrumentality of the same shaft that revolves the fire-grate.

98 is the boiler, 99 the brick-casing, and 100 the water-leg, all as shown in a patent granted to me. on the 16th day of July, 1889, for steam-boiler, No. 407,251.

I Having now fully set forth my invention, what I desire to claim, and secure by Letters Patent of the United States, is-

1. A rotary fire-grate made up of independently-movable sectors hinged at their inner ends and freely supported at their outer ends, and means interposed in the path of said revolving fire-grate for raising and lowering the said sectors as the grate revolves.

2. A rotary fire-grate made up of independently-movable sectors and one or more antifriction rollers interposed in the path of said revolving firegrate for raising and lowering the said sectors as the fire-grate revolves.

3. A rotary fire grate made up of independent sectors, means for intermittently raising and lowering the outer ends of said sectors as the grate revolves, and a second grate at the center of said revolving grate suitably hinged to form a door, whereby when the fire-grate is rotated and said door is open more or less of the contents of the fire-grate may be discharged.

4. The combination of a rotary fire-grate made up of independently-movable sectors, a rotary circular bar for supporting the outer ends of said sectors, means for pivotally supporting said sectors at the center, and one or more anti-friction rollers arranged above the level of said circular bar, whereby the independent sectors of thefire-grate will be automatically raised and lowered as the grate rc- Volves.

5. The combination of a rotary fire-grate made up of independently-movable sectors, a circular bar for freely supporting the outer ends of said sectors, a pivotal bearing for sustaining said grate at its center, intermediate connections for securing said circular bar to said pivotal bearing, a circular track for supporting said circular bar, anti-friction rollers interposed between the latter two, and means for intermittently raising and lowering said independent sectors as the fire-grate revolves.

6. The combination, with a rotary fire-grate made up of independent sectors and having controlling mechanism for raising and lowering said sectors as the grate revolves, of a second fire-grate at the center thereof, consisting of curved fingers suitably hinged together and pivoted to the apparatus, whereby an opening may be afforded at the center of the fire-grate for the discharge of more or less of the material carried thereby as the grate is revolved.

7. A firegrate made up of independent sectors pivoted at the center and freely sustained at their outer ends and an adjustable pivotal support for the same at the center, substantially as described.

8. A revolving firegrate made up of in- IOU dependent sectors, curved lingers suitably May, 1890, in the presence of the two subhinged together and pivoted at the center of scribing Witnesses.

said fire-grate and an adjustable pivotalv r W support at the center of said fire-grate and l ROHAX 5 curved fingers. Witnesses:

In testimony whereof I have hereunto set A. C. FOWLER,

my hand and affixed my sea-1, this 14th day of I DANIEL N. KIR'BY. 

